Generator cutout
- Thread starter Dkrahn
- Start date
I have the carburetor off now for a few days. So it be a while before I respond with info. I cleaned up and put new ends on the wires. I was looking at these instructions before and I am confused. Not sure why you say only middle brush is movable. Seems like they all are spring loaded and riding on the generator arm where they should.
Certimafied
Member
They are all spring loaded to keep tension on the armature, however there is one brush that can be rotated up or down around the armature the other two brushes are stationary. That third moveable brush controls generator output.
I don’t have the points type cutout, mine had already been converted to the diode/solid state cutout. But I would imagine with battery disconnected and the points closed you could check continuity between the two sides of the cutout with a multimeter. With points closed there should be continuity with little or no resistance.
I don’t have the points type cutout, mine had already been converted to the diode/solid state cutout. But I would imagine with battery disconnected and the points closed you could check continuity between the two sides of the cutout with a multimeter. With points closed there should be continuity with little or no resistance.
Patrick L.
Well-known member
The 'third brush' is the the smaller one and is mounted so it rotates to change the charge rate.
As mentioned, the other 2 normal brushes do not move. They are mounted stationary and only spring loaded to keep tension against the commutator.
As mentioned, the other 2 normal brushes do not move. They are mounted stationary and only spring loaded to keep tension against the commutator.
nkaminar
Well-known member
Dkrahn,
As others mentioned, the third brush rotates. Rotating it down increases the charging rate and rotating it up decreases the charging rate. Try change the third brush as I described earlier but make sure you view the ammeter while the engine is at a fast idle. If in doubt as to what a fast idle is, increase the rpm a little more but do not over rev the engine.
If that fails then take your generator to a shop to have it repaired or exchange it at one of the vendors, as I described earlier.
As others mentioned, the third brush rotates. Rotating it down increases the charging rate and rotating it up decreases the charging rate. Try change the third brush as I described earlier but make sure you view the ammeter while the engine is at a fast idle. If in doubt as to what a fast idle is, increase the rpm a little more but do not over rev the engine.
If that fails then take your generator to a shop to have it repaired or exchange it at one of the vendors, as I described earlier.
OK Nkaminar
lines 4-7.. I started the engine to a fast idle. I moved the generator brush all the way down and still not charging. I then checked the voltage at the generator terminal and on a 20v scale it jumped from 1.8 to 18. So I am making the assumption I need to order a cut out, and the generator is all good..Agree?? I certainly appreciate your help.
I have about 3/8" of generator brush, so I also assume that is good..
lines 4-7.. I started the engine to a fast idle. I moved the generator brush all the way down and still not charging. I then checked the voltage at the generator terminal and on a 20v scale it jumped from 1.8 to 18. So I am making the assumption I need to order a cut out, and the generator is all good..Agree?? I certainly appreciate your help.
I have about 3/8" of generator brush, so I also assume that is good..
nkaminar
Well-known member
Dkrahn,
Good work. You have done well. You now know how to adjust the 3rd brush. It seems that the generator is good. After you get a new cutout, you will have to reduce the charging (move the brush up) so that you have about 10 amps at a fast idle. If you drive the car long distances you may want to reduce the charging rate so you don't overcharge the battery. If you drive it at night a lot then you may want to up the charging rate to take care of the current the lights use. 10 amps is an average and Ford recommended adjusting it depending on how the Model A was driven.
Don't run the car without a new cutout and the generator hooked to the battery. The high voltage can damage the generator. The battery acts like a regulator on the generator.
Good work. You have done well. You now know how to adjust the 3rd brush. It seems that the generator is good. After you get a new cutout, you will have to reduce the charging (move the brush up) so that you have about 10 amps at a fast idle. If you drive the car long distances you may want to reduce the charging rate so you don't overcharge the battery. If you drive it at night a lot then you may want to up the charging rate to take care of the current the lights use. 10 amps is an average and Ford recommended adjusting it depending on how the Model A was driven.
Don't run the car without a new cutout and the generator hooked to the battery. The high voltage can damage the generator. The battery acts like a regulator on the generator.
Last edited:
eagle
Well-known member
A couple things... You replaced the ammeter as stated in previous post. If you put in a reproduction ammeter I would definitely test the old one and if its good, which is highly likely, put it back in. The repros are not very good quality. Same with the cutout, take it apart, clean it up, dress the contacts, check the insulator and put it back on. The originals are better than the repros. If you need a new one the diode type are better. If you can find it, a voltage regulator is the best.